Bryoxiphiaceae. Genus Bryoxiphium
1. Perichaetial and perigonial leaves with filiform awns 1-3(-5) mm long; middle stem leaves shortly apiculate, apicula formed mainly by shortly excurrent costae and partially by dorsal lamellae; basal laminal cells short rectangular, length/width ratio 1.6-3, weakly differentiated; dorsal lamellae mostly 1-2 cells wide, not extending to leaf base —
This species has a strongly disjunct distribution, mainly in the humid areas of the Northern Hemisphere: Europe (Iceland), North America (Greenland, U. S. A. ) and Asia (Russia and China). Its distribution in Russia is mainly in the northern Far East: Chukotka Autonomous District, Magadan Province, Kamchatka Peninsula and Kommander Islands. There are also scattered records of the species from continental regions of Siberia: Yakutia and Zabaikalsky Territory. All specimens from the Kamchatka Peninsula, previously named B. japonicum, in fact represent B. norvegicum, as confirmed by molecular data.
- Perichaetial and perigonial leaves with filiform awns (4-)6-12 mm long; middle stem leaves abruptly narrowed into awns to 0.4 mm long, awns formed by laminae, costae and dorsal lamellae; basal laminal cells subquadrate, length/width ratio 1-1.4, more or less distinctly differentiated; dorsal lamellae mostly 3-4 cells wide, often extending to leaf base —
B. japonicum is an East-Asian species found along the coastal areas of the Pacific Ocean. It is known from Japan (Hokkaido, Honshu, Shikoku, Kyushu), Korea, China, Taiwan, and the Philippines. In Russia B. japonicum occurs in the southern region of Far East: southern Kuril Islands, Sakhalin Island, coastal area in Khabarovsk Territory, Primorsky Territory, and Jewish Autonomous Province.